| 摘要 |
PURPOSE:To form a good plating layer in a welding bead part by forming a welding bead of a seam welded pipe manufactured by a metal covered steel pipe, on the lower face, cutting the outer surface of the welding bead part, and subsequently, jetting and sticking a hot dipping metal from the lower direction. CONSTITUTION:A steel band to which a Zn plating, etc. have been performed is curved to a circular section by a forming roll 11, and moved so that its butt end part is formed on the lower face. A welding bead part Aa is formed by welding the butt part by a welding roll and worked to a seam welded pipe A. Subsequently, the outer surface of the welding bead Aa is cut and finished by a cutting tool 2, and thereafter, in a non-oxidizing atmosphere, molten ZnB in a bathtub 5 is jetted by a differential pressure of a head from an opening part 3a of a nozzle 3 placed at a interval of <=2mm on the lower part of the welding bead part Aa, and the welding bead part which has been cut is plated with molten Zn. |
